LAUSR

Background Digital breast tomosynthesis (DBT) has been shown to improve screening outcomes compared with digital mammography (DM) alone. However, little is known about differences in breast cancer conspicuity between DM and DBT or by mammographic view. Purpose To compare conspicuity of breast cancers at DM versus DBT and by mammographic view, craniocaudal (CC) versus mediolateral oblique (MLO). Materials and Methods Lesion conspicuity was graded by three readers by using a 0-5 numerical scale on both DM and DBT images from combined DM and DBT studies for 197 consecutive screening-detected cancers in women (mean age, 60.4 years ± 11.1 [standard deviation]) from October 1, 2011, through December 31, 2014. Intermodality (ie, DM vs DBT) and intramodality (ie, CC vs MLO) analyses were performed. For intramodality analyses, conspicuity was analyzed by view, CC versus MLO, within the same modality. Conspicuity grades were dichotomized into low (scores 0-3) and high (scores 4 and 5) conspicuity. This binary result was assessed by using a generalized linear mixed-effects model with logit link function, random-effect intercept for reader, and compound symmetry covariance structure for lesion. Results Cancers were more likely to be high conspicuity at DBT than at DM (odds ratio [OR], 2.4; 95% confidence interval [CI]: 1.9, 3.0; P < .01). At both DM and DBT, cancers were more likely to be high conspicuity at the CC than the MLO view (DM vs DBT OR, 1.6 [95% CI: 1.3, 1.9] vs 1.7 [95% CI: 1.3, 2.1], respectively; P < .01 for both). Cancers seen at one view only were more often detected at CC than MLO for both DM and DBT (DM vs DBT OR, 1.6 [95% CI: 1.2, 2.0] vs 3.6 [95% CI: 1.9, 7.0], respectively; P < .01.). Conclusion Cancers were more conspicuous at digital breast tomosynthesis than at digital mammography. Cancers may only be detected at one of two views, and they are more likely to be seen at the craniocaudal view. © RSNA, 2019.